Data transmission, including the transmission of packets of data, comprises a well-understood area of endeavor. In many cases, and particularly when transmitting data via a wireless pathway, not all of the data may be properly received. For example, pathway conditions may be sufficiently poor so as to distort or overwhelm one or more transmission symbols as correspond to the underlying data.
Redundancy encompasses the general area of attempting to avoid or at least ameliorate such problems by transmitting more than just the basic data as described above. For example, by sending an entire message twice, or three times more, one can increase the likelihood that at least one of the transmissions will pass without undue compromise. Such a simplistic technique, of course, would be very consumptive of the communication pathway itself and could greatly reduce the total number of unique messages that could be supported by such a pathway. Consequently various other redundancy schemes have been proposed to increase the likelihood of effecting an adequate exchange of information while simultaneously minimizing usage of the supporting communication resources.
For example, present High Speed Downlink Packet Access (HSDPA) standards specify use of a hybrid-automatic repeat request (H-ARQ) scheme that makes use of a specific rate-matching algorithm. The two fundamental forms of H-ARQ are Chase combining and Incremental Redundancy (IR). The first packet data transmission will typically comprise both information bits and parity bits as correspond to the information bits. In Chase combining, each re-transmission repeats the first transmission or part of it. In IR, each retransmission provides new parity bits from the mother code to build a lower effective code rate, where the effective code rate is determined by dividing the number of unique information bits received by the number of unique information and parity bits received.
For HSDPA, this particular approach permits use of different versions of the H-ARQ redundancy algorithm. In particular, a so-called S parameter is used to indicate whether a given packet is self-decodable by itself and a so-called R parameter indicates the start point for an included stream of parity bits (and thereby in effect comprises a redundancy version selection indicator). Selection of these parameters corresponds to selection of a corresponding H-ARQ redundancy algorithm from amongst a potential plurality of candidates.
These parameters are presently selected on a relatively static basis. While a given user may make a proper (i.e., efficient) selection of these parameters in a given instance, or for a given point in time, transmission conditions can and will change (sometimes quickly and sometimes dramatically). Such changes can quickly render a given choice of parameters sub-optimum. As a result, this capability of selecting a particular approach to redundancy from amongst a plurality of candidate options does not always necessarily lead to an otherwise hoped-for improvement with respect to data throughput or efficiency.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention. It will also be understood that the terms and expressions used herein have the ordinary meaning as is usually accorded to such terms and expressions by those skilled in the corresponding respective areas of inquiry and study except where other specific meanings have otherwise been set forth herein.